The present invention relates to the field of wave pools, and in particular, to a wave pool that generates large surfing class waves and has been adapted to control breakpoints and/or reduce rip currents.
Wave pools have become popular at water theme parks in recent years. Wave pools are man-made bodies of water in which waves are created much like waves in an ocean. A wave pool typically has a wave generating machine located at one end and an artificial sloped xe2x80x9cbeachxe2x80x9d located at the other end, wherein the wave generating machine creates periodic waves that travel from one end to the other. The floor of the pool near the beach is preferably sloped upward so that as the waves approach, the floor causes the waves to xe2x80x9cbreakxe2x80x9d onto the beach.
One problem associated with creating waves in wave pools is that rip currents, similar to those that exist in nature, can be created. For example, rip currents can be formed by the reverse flow of water (down the sloped beach) flowing against oncoming waves, which can detrimentally affect how water and energy dissipate, i.e., it can cause waves to break sooner and more dramatically, which in turn, can generate more white water and mass transport of water onto the beach. This not only makes surfing and water skimming maneuvers more difficult to perform, but it can also lead to an increased risk of injury.
In recent years, this problem has worsened due to the use of more powerful wave generating machines in wave pools designed to produce larger waves. These machines are typically installed in pools that are larger and have deeper floors than conventional wave pools. The object has been to produce larger and more frequent waves, and to enable surfing and water skimming maneuvers to be performed thereon.
Such wave pools have several disadvantages. One is the increased occurrence of rip currents, with their attendant risks, which can make it more difficult for participants to perform surfing and water skimming maneuvers safely. Second, wave pools that are larger are inherently more expensive to construct. In this respect, many wave pools are installed in areas where land is scarce, and therefore, building larger wave pools, simply to increase wave size, is not often cost-effective. This is particularly true where wave pools are already installed and significant effort and expense would be needed to modify and enlarge them. Third, where wave pools are used to host surfing exhibitions and competitions, making wave pools larger has the detrimental effect of forcing spectators (who are normally seated on bleachers or grandstands immediately behind the beach) further away from the waves, which can leave spectators further away from the action. This is particularly true given that one way to make wave pools safer is to decrease the slope of the pool floor, which in turn increases the distance between where the waves break and where the spectators are located. Fourth, in order to maximize the productive asset value of a wave pool, it is optimal to attempt to increase the frequency of wave generation in order to allow an increased number of riders per hour with a corresponding increase in revenue per hour using the same asset base. Of consequence with increased wave frequency is increased water movement with resulting increased production of rip currents. A shorter time period between each wave also means there is less time for a fallen rider to move out of the way of a new rider on a succeeding wave. Finally, competition surfing class wavepools will often employ rapid changes in pool bottom topology in order to cause preferred plunging style breakers. Abrupt bottom contours are viewed as hazardous by governmental health and safety organizations, given the increased potential for bathers to loose their footing and inadvertent head injuries and diving accidents.
What is needed, therefore, is an improved wave pool design which enables larger and more frequent quality waves to be produced in a safe manner, without having to increase wave pool size, while at the same time, enabling the control of wave breaking characteristics and reduction of rip currents, which would otherwise be detrimental to wave formation.
The present invention represents an improvement over previous wave pool designs insofar as it enables control over the breakpoint and reformation of a wave and reduces detrimental rip currents, while allowing larger and more frequent quality waves to be created, without increasing pool size or floor design hazard. The present invention is able to accomplish this by: (1) providing one or more grates on the pool floor and along the beach side of the pool to allow water and energy from a generated wave to pass through into a cavity below, such that wave breaking characteristics can be controlled, reverse flow minimized, and rip currents reduced; and (2) providing a spatial sequencing in pool bottom topography that allows a generated swell to break, reform into an unbroken swell, and then break again.
Wave pools are typically constructed like large swimming pools, with a sloped floor on one shallow end, wherein a wave generating device is provided at the deep water end, to generate periodic waves that travel across the pool to the shallow end where the beach is located. To diminish the size of the wave as it approaches the shore, wave pools can have side walls that fan out and expand toward a beach area, as well as a sloped inclined floor which causes waves to break. The sloped inclined floor near the beach can cause water moved by the energy of a progressive wave to roll-up the inclined floor until the wave energy is spent, wherein gravity then causes the water to flow back down against other oncoming waves, thereby creating an undercurrent of water that forms rip currents.
In one aspect, the present invention represents an improvement over previous wave pool designs in that it is specifically adapted to reduce rip currents that normally occur in and around the beach area. While energy from a wave breaking along the beach normally creates white water and mass transport of water onto the beach, the after-break zone and beach area of the present invention preferably comprises a grated floor that allows water to pass through into a cavity below, away from the beach surface and thus avoiding a large surge run-up on the beach. That is, as each wave breaks and its forward momentum causes water to flow up onto the beach, water is allowed to pass through the grated floor, and into the cavity below, such that virtually none of the water is allowed to flow back onto the inclined floor of the beach and flow back down again against the oncoming waves. In such case, most of the water that would otherwise flow up the beach simply passes through the grated floor, and is effectively removed from the beach to reduce rip currents.
Reducing rip currents in this respect enables the frequency of the waves to be increased, i.e., more periodic waves can be generated in a shorter amount of time, since there are no rip currents to adversely affect each oncoming wave. In a commercial wave pool environment, a greater wave frequency advantageously results in increased rider throughput, which means greater revenue and a higher rate of return on fixed assets. Reducing rip currents also allows the waves to be made larger and more powerful without having to increase pool size, nor the risk of injury to participants. It also makes more efficient use of existing resources, such as land, since wave pools of the present invention do not have to be enlarged to increase wave size and quality. In fact, the present invention can make it so that wave pools can be made smaller and more compact without sacrificing performance and safety. Also, as mentioned above, an additional benefit of the present invention is that spectator viewing areas behind the beach can be located closer to the waves, which can enhance the viewers"" experience. Finally, by introducing a grated false floor near the bottom of the pool, the true pool bottom can be made steeper, which in turn, can help create larger and more powerful waves, without changing the effective floor depth (for the participants) and without increasing the risk of drowning associated with deeper pools.
Another aspect of the present invention is that it preferably has a circulating means to allow water to circulate from one end of the pool to the other, and then back again, without interfering with wave formation. As the wave generating machine generates waves, the waves will travel across the pool and onto the beach area, but as water flows through the grated floor, and into the cavity below, water will tend to build up and spill over back onto the sloped floor, thereby defeating the purpose of the invention, unless a circulation means is provided.
The circulation means of the present invention can be an underground channel that extends under the pool floor and connects the beach end of the pool to the end where the wave generating machine is located. This way, as wave energy pushes water toward the beach, and water on that end of the pool effectively builds up, water can be diverted away from that end and back towards the wave generating machine (on the other end), thereby helping to maintain the level of water in the pool at both ends in substantial equilibrium. And, by enabling water to be recirculated back to the other end of the pool within an underground channel, the wave formations in the pool are not disturbed thereby.
The circulating means of the present invention can be operated either with a pump or without a pump. Without a pump, the channel under the pool floor can be adapted so that the restoring force of gravity alone can help maintain the level of water in the pool in equilibrium. That is, as water is pushed toward the beach and into the cavity, a high pressure area is created, i.e., the water level at that end of the pool rises. At the same time, as water is pushed away from the wave generating machine, a low pressure area is created, i.e., the water level at that end decreases. Accordingly, as water seeks its own level, the difference in pressure between the two ends of the pool can cause the level of water to reach equilibrium naturally, i.e., by causing water to flow through the underground channel in the appropriate direction.
When a pump is provided, the pump can be used to help circulate water in the appropriate direction, which is away from the beach end, and towards the wave generating end. In this embodiment, the pump preferably runs at a predetermined flow rate depending on the frequency and volume of the waves being generated by the machine. For example, when the wave generating machine is operated at high levels, the pump would operate at a relatively high level to ensure that an equilibrium can be achieved. On the other hand, when the wave generating machine is operated at low levels, the pump would also operate at a relatively low level. In this respect, the pump can be located within the underground channel, or can be incorporated within the wave generating machine. When incorporated with the wave machine, the pump can be combined with a tank reservoir to surge and generate waves.
In one embodiment, the wave generating machine is located above the underground channel (in front of the return) so that water can recirculate under and behind the wave generating machine, and then be drawn directly from the channel so that it can be used to create additional waves. In this case, an opening (return) in the channel is preferably located behind the wave generating machine, i.e., on the side opposite the beach area, so that water can circulate behind the wave generating machine, and, as the wave generating machine draws water from the channel, it can direct wave energy away from the return and toward the beach area. This ensures that the wave energy from the machine is not directed against the flow of water inside the channel. In such case, no other mechanism would be required to direct energy and water away from the channel.
In another embodiment, the wave generating machine can be located at the edge of the pool opposite the beach area, wherein water could be drawn from the underground channel through an opening in front of the machine adjacent the bottom of the pool. In this embodiment, the wave generating machine draws water from the channel through a grate in the channel. A separate mechanism is preferably provided to direct wave energy away from the channel, which enables water and energy generated by the wave generating machine to be directed away from the channel, such that energy is not directed against the channel flow.
In one aspect, the sloped floor along the beach area can be extended up above the mean standing water level of the pool. This way, as the waves break and water is pushed up onto the beach area, water will travel up and over the upper edge of the floor. Once water flows up and over the upper edge, it falls into the cavity below, and cannot flow back down into the pool against the oncoming waves (unless the water level in the cavity fills up). This helps reduce the tendency of the wave pool to create rip currents and additional rebounding effects, which can occur as water traveling through the grated floor hits the far wall under the grated floor, wherein the impact can otherwise cause water to rebound and flow back against the oncoming waves.
In another variation of the above embodiment, the far wall below the grated floor can be sloped or inclined so that as water passes through the grated floor and into the cavity, the energy from the waves can be dissipated gradually, i.e., as it climbs up the slope or incline, in which case the rebounding effects can be reduced. This aspect is particularly advantageous in embodiments where the upper edge of the floor does not extend above the mean standing water level, or where there is no pump or other mechanism to circulate water away from the beach toward the other end of the pool, wherein water could otherwise build up and fill the cavity and overflow back into the pool.
The relationship between the depth of the water over a solid pool floor and the breakpoint or reformation to an unbroken wave is adequately described by conventional wave physics encompassing wave height, speed, frequency, etc. The subject invention uniquely describes a spatial relationship between pool floors that, due to changes in topography, cause a wave swell to break, subsequently stop and reform to a smaller unbroken wave swell, and then break again.
In this embodiment, the pool floor can be adapted to have additional alternating inclined and deep water grated floor areas, wherein a subject wave can break, reform and break again, etc. This embodiment makes use of basic wave physics, i.e., the breaking characteristics of a wave is a function of pool floor depth. The first inclined floor section is adapted to cause a first break, but then terminates (where the adjacent grated deep water floor begins). Then, the open characteristics of the grated floor suspended over a deep water cavity allows the wave to xe2x80x9cfeelxe2x80x9d that it is in deeper water, so that as the wave progresses and reaches the deeper water area, the wave stops breaking and reforms into an unbroken wave. By terminating the first inclined floor section and providing a grated floor suspended above a deep water hollow beyond it, the wave formation can transition from unbroken, to breaking, to unbroken, i.e., as the wave progresses across the pool. This is done in correspondence with a series of alternating inclined floor sections succeeded by deep water hollow sections.
It should be noted that one side effect of the grated floor is that it causes a loss of wave energy due to friction and thus a corresponding reduction in wave size as the wave progressively moves over the grated floor and towards the beach. Consequently, to maximize wave size and still take advantage of wave reformation and rebreaking, the grates could be eliminated, and a solid floor with variations in pool depth from one section to another can be provided. As a trade-off for grate elimination, however, the beneficial effects of enhanced rider footing and stratification of rip current flows below a false grated floor would be lost. Accordingly, removable grates could be used to allow dual mode functionality and is preferred.
If additional waves are desired within the pool, the pool can be adapted to have additional alternating inclined and deep water (grated) floor sections. That is, as the wave travels forward, it can, if desired, be adapted to encounter another, i.e., a second, inclined floor section within the pool, wherein another breaking wave formation can be generated, wherein again, another deep water (grated) floor can subsequently be provided, to enable the wave to stop breaking and reform. This starting, stopping and restarting of a wave""s breaking characteristics, as it progressively moves from one end of the pool to the other, advantageously allows an arithmetic increase in the number of surfer take-off points and maximizes, from a surfer""s perspective, the most valuable part of the wave, i.e., the transition area between breaking curl and unbroken wave.
Additionally, the ability to control a wave""s formation and how it breaks within the pool maximizes the number of rides derived from any given wave and the length of such rides. That is, surfable waves can be created wherein a surfer can catch the first break point of a given wave moving toward the beach; this same wave can subsequently be re-used (caught) by a second surfer catching the reformed wave. Furthermore, if the wave breaks obliquely to the pool beach, then, each surfer gets to take advantage of the entire width of the pool for maximum ride length enjoyment.
An additional benefit to deep water hollows subsequent to an inclined floor break area is enhanced operational safety. In the event of a rider falling, the reform area deepens and the wave stops breaking. This allows a fallen surfer to quickly recover and avoid collision with an inside rider. Also, by providing alternating sections of inclined and deep water (grated) floor areas within the pool, the entire pool can be used to create a multiplicity of surfable waves, as opposed to a solitary periodic wave found in typical wave pools. Due to the initial breaking of the outside wave, the inside reform, and the subsequent inside breaking, waves are reduced in size as compared to the outside wave. However, this allows the inside wave to be the ideal break for beginners. Furthermore, the distance that a reformed swell travels before encountering a subsequent inclined slope portion of the pool floor must also be considered in maximizing the functionality and safety of the wavepool. Ideally, this distance is kept to a minimum in order to reduce pool size and associated costs of construction and operation. However, this distance must be sufficient to avoid mixing outside wave riders from inside.
These alternating inclined and deep water (grated floor) areas can be configured in virtually any manner to produce the desired results. For example, the inclined and deep water (grated) floor areas can be extended normal to the travel direction of the waves, or diagonally, in which case the waves that are formed travel at an oblique angle in relation to the beach. The inclined floor areas can also be adapted so that they extend across only a portion of the width of the pool, wherein wave formations can be generated in isolated sections of the pool. In their broadest forms, the inclined and grated floors can be separated from one another, and placed on top of each other, wherein the grated floor can be extended above the inclined floor. In such case, the grated floor is able to support the participants, while the inclined floor is adapted to create the desired wave formations. For example, the inclined floor can be made to have different inclinations and depressions to form unique wave formations, while at the same time, the grated floor can be extended horizontally (separate from and above the inclined floor) to provide a relatively level and safe support for the participants.